When they near the ideal spot for the Ultibed to be place down, they see a large gap that must be crossed, and learn that to get to the other side they have to find the five remaining Master Pi'illos which hold the Somnom Stones. Once all of the Somnom Stones are collected, the Bros. can assemble a long enough track to reach the other side and hit an ! Block to assemble a complete set of tracks, making the Somnom Stones obsolete.